Science for Environment Policy FUTURE BRIEF: Underwater Noise June 2013 Issue 7 Revised version* Environment *This version of the report, published on 30 October 2013, replaces the earlier versions published on 28 June 2013 and 2 September 2013. Science for Environment Policy This Future Brief is written and edited by the Science Underwater Noise Communication Unit, University of the West of England (UWE), Bristol Email: [email protected] Contents To cite this publication: Science Communication Unit, University of the West of England, Bristol (2012). Science for Environment Policy Future Introduction 3 Brief: Underwater Noise. Report produced for the European Types and sources of underwater noise 4 Commission DG Environment, June 2013. Available at: http://ec.europa.eu/science-environment-policy Impacts of underwater noise on marine life 4 The ultimate effects of underwater noise on people and society 6 Acknowledgements We wish to thank Rene Dekeling of the Ministry of Monitoring underwater noise 6 Infrastructure and the Environment, Netherlands, and Mark Reducing the impact of underwater noise 7 Tasker of the Joint Nature Conservation Committee (JNCC), Knowledge gaps 7 UK, for their input to this report. Final responsibility for the content and accuracy of the report, however, lies solely with Summary 7 the author. Images Page 3: ©istockphoto.com/ultramarinfoto. Page 4: Corrigenda ©istockphoto.com/Brad Martin. Page 4: ©istockphoto.com/ crisod. This version of the report, published on 30 October 2013, replaces the earlier versions published on 2nd September 2013 and 28th June 2013. Following consideration of comments received on the Underwater Noise Future Brief, elements of the text have been modified as follows: Amendments made on 30 October 2013: Section 1, Types and sources of underwater noise, page 4. This has been amended to acknowledge that "mid frequency naval sonar may be harmful to marine mammals". About Science for Environment Policy Section 2.1. Physical damage, page 4. To better reflect the scientific consensus, the second paragraph has been revised. It draws attention to research (Frantzis, 1998) that indicates that Science for Environment Policy is a free news noise produced by military sonar can cause stranding in beaked whales and provides information and information service published by the European taken from a report by the International Council for the Exploration of the Sea (2005) on the possible mechanisms that may lead to stranding. Commission’s Directorate-General Environment, which provides the latest environmental policy- Amendments made on 2nd September 2013: relevant research findings. Introduction, page 3. To acknowledge existing uncertainty surrounding the evidence, the statement ‘Currently these requirements pose a challenge, particularly considering the limited Future Briefs are a feature of the service, evidence on sounds impacts” has been changed to: ‘Currently these requirements pose a challenge, introduced in 2011, which provide expert forecasts particularly considering the difficulties of generalising based on existing evidence from a range of of environmental policy issues on the horizon. In different species and noise sources.” addition to Future Briefs, Science for Environment Section 2.4. The balance of effects, page 6. To acknowledge existing uncertainty surrounding Policy also publishes a weekly News Alert which the evidence, the statement "As current evidence suggests that noise only rarely kills marine animals, is delivered by email to subscribers and provides those pressures that do very often kill marine species, such as fishing and pollution, could be considered accessible summaries of key scientific studies. more important”, has been changed to “As it remains an open question how many marine animals are killed by noise, those pressures that are known to kill marine species, such as fishing and pollution, could be considered more important.” http://ec.europa.eu/science-environment-policy Summary, page 7. To account for the broad range of noise sources, the statement the summary “Underwater noise from shipping, energy production, fishing and tourism”, has been modified to “Underwater noise from sources including shipping, energy production, fishing and tourism”. Keep up-to-date The following references have been added to support information provided in the report: Subscribe to Science for Environment Policy’s Frantzis (1998); International Council for the Exploration of the Sea (2005); Løkkeborg et al. (2010). weekly News Alert by emailing: [email protected] The contents and views included in Science for Environment Or sign up online at: Policy are based on independent research and do not necessarily reflect the position of the European Commission. http://ec.europa.eu/science-environment-policy 3 Introduction Underwater Noise The oceans are increasingly exposed to sounds from human activities, such as shipping and the building of foundations for offshore construction projects. What impact do these sounds have on species that inhabit the marine environment? This Future Brief from Science for Environment Policy explores existing research on the ecological effects of underwater sound. Key gaps in our knowledge are also highlighted, and potential strategies for reducing negative impacts on marine species are outlined. Underwater noise is an important aspect of the Marine addition, under the Habitats Directive, noise is regarded Strategy Framework Directive (MSFD), which aims as a disturbance that may have detrimental effects on to achieve good environmental status (GES) of the wildlife, including marine life. In particular, it prohibits European marine environment by 2020. Noise is deliberate disturbances that affect populations of defined here as sound that causes negative effects. protected species and their ability to survive, breed and rear their young (European Commission, 2007). GES is defined according to a set of 11 broad indicators or ‘descriptors’1, including those focusing on biological However, as part of the MSFD roadmap, EU Member diversity, fish populations and marine litter. Descriptor States will need to address sound more directly and 11 focuses on energy inputs, including underwater work together in shared waters to achieve GES as noise. In February 2012, the MSFD Technical Subgroup defined under descriptor 11. This will involve defining on Underwater Noise delivered a report to the European potentially harmful levels of underwater sound, and Commission, providing guidance on implementing putting in place monitoring systems (by 2014) and aspects of the MSFD under descriptor 11 (Van Der measures (by 2015) that will be needed if underwater Graaf et al, 2012). sound needs to be reduced. Currently these requirements pose a challenge, particularly considering the difficulties Some existing measures indirectly control sound in of generalising based on existing evidence from a range European waters. For example, permits for pile-driving of different species and noise sources. – the sinking of pole-like foundations – are granted based on Environmental Impact Assessments. In 1. http://ec.europa.eu/environment/water/marine/ges.htm UNDERWATER NOISE 4 1. Types and sources of underwater noise Sound travels rapidly through water – four times faster than through air. As in open air, sounds are transmitted in water as a pressure wave. They can be loud or soft, high- or low-pitched, constant or intermittent, and volume decreases with increasing distance from source. Sound pressure is most commonly measured in decibels (dB). Underwater noise (as viewed by the MSFD) has been divided into two main types: • Impulsive: loud, intermittent or infrequent noises, such as those generated by piling, and seismic surveys • Continuous: lower-level constant noises, such as those generated by shipping and wind turbines These two types of MSFD-related noise have different impacts on marine life. In addition, mid-frequency naval sonar may be harmful to marine mammals. The frequency, or pitch, of the noise is also important, as animals are sensitive to different frequencies. For instance, most of the noise produced by leisure boats is low frequency, below 1.5 kilohertz (kHz). Although most sensitive to sounds above 15 kHz, bottlenose dolphins could be disturbed by these boat noises because Studies suggest that the loud noises used by seismic survey ships to map the geology of the oceans and seas can they hear in the wider range 0.075 - 150 kHz and some affect the hearing and behaviour of some marine species. calls, thought to be food-related, are below 2 kHz (Rako et al, 2013). The underwater environment is becoming noisier in some areas as it is increasingly exploited (Subsidiary ‘The underwater environment is becoming noisier in some Body on Scientific, Technical and Technological Advice, 2012). Diminishing resources mean that we are turning areas as it is increasingly exploited.’ to the oceans to generate our energy, by building offshore installations, and to mine precious minerals, and fishermen use sonar to tell them where to fish. 2. Impacts of underwater noise on marine life Most of the research on the impacts of underwater noise has until 2.1 Physical damage recently focused on marine mammals, such as harbour porpoises. There has been less work to understand its effects on fish and other species. Studies on underwater noise have established that noise can cause permanent injury in some marine animals (Popper et al, 2005). In the In theory, the behaviour of any species with the ability